The present invention relates to an improved coil winding apparatus having a traverse mechanism for moving a wire supply part in the axial direction of a coil bobbin in synchronism with the rotation of the bobbin so as to wind turns of wire on the bobbin in alignment, and to an improved coil winding method for doing the same.
When turns of wire are wound in alignment on the bobbin of a coil, a nozzle which supplies the wire is moved in an axial direction of the bobbin in synchronism with the rotation of the bobbin. The nozzle is moved at a pitch equal to the diameter of the wire on each rotation of the bobbin so that an alignment of wire turns is achieved.
In a traverse mechanism of a prior art coil winding apparatus, when the wire is wound, a nozzle displacement mechanism moves the nozzle a distance corresponding to the wire diameter, and when the bobbin is removed or other operations are performed on the bobbin after winding is finished, the nozzle is moved to a position in which it does not interfere with these operations.
Specifically, when the bobbin is removed, the nozzle must be displaced to a position which does not overlap with the bobbin, so the range of displacement of the nozzle is much larger than the width of the bobbin. The displacement speed and displacement distance of the nozzle are different during coil winding and when the bobbin is removed, however both of these displacements are performed with one traverse mechanism, so the traverse mechanism necessarily has a large range of motion and is bulky.
However, in this bulky traverse mechanism which has a large range of displacement, there is a limit to the resolution that can be obtained in performing small pitch displacements such as when winding a fine wire, and it cannot be displaced with a precise pitch.
When a narrow width is traversed at high speed as in the case of a transformer or ignition coil, if the nozzle is moved at high speed by a bulky traverse mechanism, vibration occurs when the traverse mechanism displaces and particularly when the displacement direction is reversed. Moreover, as the bulky traverse mechanism is also heavy, it does not stop immediately even if the displacement is stopped, and it does not reverse immediately even if the displacement direction is reversed. In other words, if the traverse mechanism is large, its inertia is large, and its ability to perform displacements and reverse its direction of motion is poor. Due to these factors, in a prior art traverse mechanism, the wire was not fed out smoothly, the alignment of coil windings sometimes broke down, and high speed, precise winding of wire turns in alignment was difficult.
For example, ignition coils may be broadly distinguished as bank-wound ignition coils and section-wound ignition coils, but in both cases, the wire turns are wound in alignment at high speed on plural narrow widths of a bobbin shell. In a prior art, bulky traverse mechanism, there was a problem regarding resolution and vibration. With bank-wound ignition coils, the winding alignment sometimes broke-down, and with section wound ignition coils, high speed, precise winding of wire turns in alignment was difficult.
It is therefore an object of the present invention to provide a coil winding apparatus and coil winding method wherein a wire supply nozzle can be displaced by an accurate pitch even when a fine diameter wire is wound, vibration does not occur in the case of high speed displacement or reverse displacement, a fast response is achieved when the direction of motion is reversed, feeding of the wire is not prone to error, the coil winding alignment does not break down, and the wire turns can be precisely wound in alignment at high speed.
To achieve the above object a coil winding apparatus of this invention comprises a spindle on which a bobbin is fitted, a wire supply part for feeding out a wire and winding it around the bobbin, a mechanism which causes the spindle and wire supply part to perform rotation relative to the spindle axis, and a traverse mechanism which causes the spindle and wire supply part to perform relative displacement in the axial direction of the spindle. The traverse mechanism comprises a first traverse mechanism and a second traverse mechanism which operate independently of one another.
This invention also provides a coil winding method which uses a spindle on which a bobbin is fitted and a wire supply part for feeding out the wire and winding it around the bobbin are provided, the spindle and wire supply part are made to rotate relative to the spindle axis, and the coil is wound while the wire supply part and the spindle are made to perform relative displacement in the axial direction of the spindle due to the first and second traverse mechanisms.
According to this invention, a traverse mechanism is provided with a first traverse mechanism and a second traverse mechanism which operate independently of one another, the first traverse mechanism and second traverse mechanism being operated selectively or in conjunction with one another when winding a wire or removing a bobbin. When winding a wire coil, the mechanisms are moved with an optimum displacement pitch and speed, the displacement is smooth, the coil winding alignment does not break down, and the coil can therefore be wound accurately. When removing a bobbin, the wire supply nozzle can be moved to a position with high speed where it does not interfere. Hence, the entire winding process can be performed more efficiently.
The details as well as other features and advantages of the present invention are set forth in the remainder of the specification and are shown in the accompanying drawings.